High angular-resolution automated visible-wavelength scanning angle Raman microscopy.
Anal Chim Acta
; 848: 61-66, 2014 Oct 27.
Article
en En
| MEDLINE
| ID: mdl-25263117
ABSTRACT
A scanning angle (SA) Raman microscope with 532-nm excitation is reported for probing chemical content perpendicular to a sample interface. The instrument is fully automated to collect Raman spectra across a range of incident angles from 20.50 to 79.50° with an angular spread of 0.4±0.2° and an angular uncertainty of 0.09°. Instrumental controls drive a rotational stage with a fixed axis of rotation relative to a prism-based sample interface mounted on an inverted microscope stage. Three benefits of SA Raman microscopy using visible wavelengths, compared to near infrared wavelengths are (i) better surface sensitivity; (ii) increased signal due to the frequency to the fourth power dependence of the Raman signal, and the possibility for resonant enhancement; (iii) the need to scan a reduced angular range to shorten data collection times. These benefits were demonstrated with SA Raman measurements of thin polymer films of polystyrene or a diblock copolymer of polystyrene and poly(3-hexylthiophene-2,5-diyl). Thin film spectra were collected with a signal-to-noise ratio of 30 using a 0.25 s acquisition time.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Anal Chim Acta
Año:
2014
Tipo del documento:
Article
País de afiliación:
Estados Unidos